This SSA passed in front of the lower and middle trunks of brachial plexus
, then it penetrated upper trunk through the gap between its anterior and posterior divisions.
Supraclavicular approach gives the most effective block for upper extremity and is carried out at the level of trunks of brachial plexus
. (1) the plexus is blocked where it is most compact.
In a cadaveric study carried out by Reiner and Kasser , the dorsal scapular artery, found between the trunks of brachial plexus
, was found to be originating from subclavian artery in 75% of cadavers.
The upper and middle trunks of brachial plexus
were involved in our patient.
The supraclavicular approach to brachial block is carried at the level of trunks of brachial plexus
. It provides most effective blockade since plexus is blocked at the middle of Brachial plexus, resulting in homogenous spread of anaesthetic drug throughout the plexus.
The subclavian artery and the middle and lower trunks of brachial plexus
were found to traverse beneath this variant slip, thereby decreasing the space between scalenus anterior and scalenus medius muscles for their exit and thereby predisposing to neurovascular compression.